Excellent article. I've got a personal loathing for the word "team" in a corporate context. It is constantly used to imply a responsibility beyond what you are actually paid for. No, you are not "letting the team down" if you go home on time. You are working your contracted hours. If anyone has let the team down, it is management for not hiring adequate staff.
And no - unless you are a member of the emergency services paid to be on call, that "urgent" call or email over the weekend can damn well wait until Monday.
I'm so glad I don't work in such idiotic environments anymore.